Aortic valve neocuspidization with in-body tissue-engineered autologous membranes: preliminary results in a long-term goat model

OBJECTIVES: Aortic valve neocuspidization has shown satisfactory clinical outcomes; however, autologous pericardium durability is a concern for young patients. This study applied an autologous collagenous membrane (Biosheet®), produced by in-body tissue architecture, to aortic valve neocuspidization and investigated its long-term outcome in a goat model. METHODS: Moulds were embedded subcutaneously in 6 goats. After 2 months, Biosheets formed in the moulds. We performed aortic valve neocuspidization using a portion of the sheets with a thickness of 0.20-0.35 mm, measured by optical coherence tomography. Animals were subjected to echocardiography and histological evaluation at 6 months (n = 3) and 12 months (n = 3). As a control, the glutaraldehyde-treated autologous pericardium was used in 4 goats that were similarly evaluated at 12 months. RESULTS: All animals survived the scheduled period. At 6 months, Biosheets maintained valve function and showed a regeneration response: fusion to the annulus, cell infiltration to the leaflets and appearance of elastic fibres at the ventricular side. After 12 months, the regenerative structure had changed little without regression, and there was negligible calcification in the 1/9 leaflets. However, all cases had one leaflet tear, resulting in moderate-to-severe aortic regurgitation. In the pericardium group, three-fourths of the animals experienced moderate-to-severe aortic regurgitation with a high rate of calcification (9/12 leaflets). CONCLUSIONS: Biosheets may have regeneration potential and anti-calcification properties in contrast to autologous pericardium. However, in order to obtain reliable outcome, further improvements are required to strictly control and optimize its thickness, density and homogeneity.